Recently, a lithium-ion secondary battery has been the focus of research as a secondary battery, which is a key for putting electric and hybrid electric cars into practical use. The lithium-ion secondary battery has a configuration in which flat electrodes are formed on surfaces of respective metal foils serving as a current collector and a multiple of the electrodes and the metal foils are stacked together in order to improve energy density. The electrode is formed by applying an electrode material including an active material, a solvent, or the like on a metal foil, drying the electrode material, pressing the electrode material and so on.
For example, according to a technique described in Japanese Patent Application Laid-Open No. 2004-327203, an electrode material is continuously applied on a surface of a long metal foil while conveying the metal foil, and the electrode material is then dried by inductive heating. In particular, an inductive coil used for inductively heating the metal foil is opposed to the surface of the metal foil, and the metal foil is continuously subjected to inductive heating while moving the metal foil.